Hey Everyone! First post, new(ish) Corvette Owner of first vette. Got my C4 a few months ago and the FX3 wasn't working due to an Actuator problem. 92 with 57k miles, 6 speed, very happy owner.

Was throwing a Code for Front left actuator so I replaced the actuator with the rebuilt Metal Gear from CaptainZ CNC (which from what I can tell is worth every penny, new gear looks like a BOSS as compared to the plastic one). Replaced the Shock gear with a new stronger one too. Wasn't especially difficult except for the pin holding the shock gear to the shock which was a royal pain.

SRC Light is now off on the dashboard. (Hooray!)

That all being said, should I notice a extreme difference between the settings? I only ask because I don't really. I can feel the difference on ramps for the interstate in terms of handling, but otherwise it's hard to tell. I think I feel a minor difference, but I'm wondering if the car's FX3 system had been out of service for so long that the shocks got old and the difference isn't as noticeable. Is this something that could fix it self by using the system to revive it?

I figure the best step is to rebuild or replace the shocks, but at $1k for just the parts brand new I thought I'd Pop the forum Cherry and ask for opinions. I plan on replacing the shocks at some point, but wasn't thinking it would be an immediate thing. Lots of people I've noticed replace the FX3 with standard shocks. Not interested in that option at this time, the car came with the FX3 and that's the way I'd like it to stay. Just concerned it's not working right.

Also sorry if this has been asked before, I've read all I can about the FX3 system, but I still have the question.

Thanks!

 

The FX3 shocks are gas charged but also have some oil in them. In fact Bilstein slightly overfills them with oil to allow for some seepage.

At 57K, the shocks could be worn out but if they are dry on the outside, I would think they should be OK. But Bilstein can easily rebuild your shocks and at a cost far less than buying new.

Bilstein can even provide a custom valving based on how the car may be used. A Forum member worked with Bilstein years ago to create a custom valving called "Morraca" or something similar. Doug Rippie Motorsports has (or had) a custom controller that allowed for the use of replacable PROM's to further tailor the system. Bilstein does the rebuild work at their facility in Poway, CA near San Diego.

As far as differences in stiffness, the FX3 system is always making minute adjustments within each of the 3 positions of the console switch. Some of the tiny adjustments will actually allow for overlaps in stiffness based on vehicle speed (the VSS at each wheel provides input to the FX3 controller). So the shocks can be stiffer with the switch set to TOUR and a speed of 70 MPH than when the switch is set to PERF and the speed is 25 MPH.

When I had my '92, I could easily tell the difference on the freeway when gong over expansion strips. The PERF setting would give me a stiff bump feel going over them and in TOUR, I felt nothing.

 

For my track car I ditched the FX3 system and setup the FX3 shocks manually. If you look at these two charts you can see that the shocks change valving based on speed.





The shocks don't even reach full stiff until 160 mph! At regular driving speeds (50-70 mph) there is not much difference between settings. When I got rid of my actuators I turned the gear on each shock to full stiff and zip tied it in place. It was NOTICEABLY stiffer and handled much better on track. I think the FX3 system is overrated, but that may be just me.

 

For a track car FX3 is over rated. For a dual purpose street/track car it is a good system. Gives a softer ride in touring and firm in performance. At least if you system is working right.

Try this, set it in touring and quickly but safely flick the car back and forth. Feel the car move around on the suspension before it takes a set. Now set it in performance and do the same thing. You SHOULD notice in performance mode that it feels quicker and tighter less body motion and sharper responses.

FYI, I do believe the custom controllers can be made to give you a soft ride in touring and a Full stiff setting in performance at all speeds.

WAY cheaper to rebuild than replace unless you get some junk shocks.
Bilstein, Koni, QA1, maybe a few others are they way to go.

For street only use some KYB's might be acceptable in my book. I'd just stick with the Bilstein shocks if I where you.

 

Thanks for the advice!

The shocks are Dry on the outside so I too would assume they are ok. They are supposed to last a relatively long time from what I understand as well, but being 20 years old who knows.

If I redo the shocks I will probably spend the extra $100 each over the rebuild for new ones as they come with a Lifetime Warranty. You can find them over at eshocks for $187per. Will install them over the winter while the season here in Indiana prevents driving.

I will take it out the next occasion I get and try the swerving safely to test the difference. I thought I felt a difference on the Highway Onramp, but the system has never worked since I've owned the car so it's hard to tell. I will also start looking for some expansion strips on the freeway, not sure we have any around here as we don't really have any toll booths in the area, but that sounds like a great indicator too.

Thanks for the Tips!

 

I will tell you how well the FX3 works in my car.... I drove it for ten days flipping the switch between the three settings, thinking there was a huge difference... Then while I was checking my wheel bearings and brakes, I noticed there was no actuator on top of my front shocks, it was tied up to the wiring harness. Found out there should be a warning light on the dash that lights up at startup.... Nothing. Worked so good I knew I felt different settings..... Ain't it funny how we as silly humans perceive things?

 

If you get a chance to enter an autocross event, you will easily feel the difference between the three settings. Even more so if you do a track day You can also feel the difference on twisty roads; the selector switch immediately changes the setting and the controller makes small changes based on speed.

The shocks being dry on the outside is a good thing. But with the slight overfill of oil when they were new, a very light film of oil is no problem.

 

i've got a 92 with fx-3 , can't feel a thing around town. but, from what i've read the car will handle better in the turns. i take it to the limits all the time.

 

I'm not sure I'd say "WAY" cheaper.

Right now eshocks is selling FX3 shocks for $755 for a set of four (free shipping). Bilstein is $100 apiece to rebuild, plus shipping and that's IF they need no other work. If you figure shipping into the mix you'll spend $300-350 more for new shocks. If you check Ebay you'll see find that you can easily get $300 plus for a set of used FX3 shocks, which makes it just about a wash.

Unless you're getting some kind of custom valving, I'd much rather have a brand new pair then a rebuilt pair...............especially if the price is a wash.


To the OP, I'm currently contemplating the same exact decision. The original FX3 shocks are completely shot on my 91 with 133k on the clock. I had been going back and forth between rebuild and replace. Eshocks recently lowered their price for FX3 shocks by $15 apiece or so. That pretty much sealed the deal for me. I'm buying a new set and selling my old ones.

 

I definitely have a light that does a checkup and shuts off (now) to say the system works so I'm assuming it all checks out.

I absolutely noticed a difference going around a few on ramps to the highway and with different settings in a parking garage. It wasn't a black and white difference, but knowing how the car feels I could feel it.

Th custom controller may be what I should look into as on the street I don't feel much difference between the settings over all even though I can feel a difference now that I know where to look...

When I replace the shocks (probably next year after I've thought about it) I'm going to get new ones and sell these as well. Seems worth it to me for the lifetime warrant assuming I can find a good price.

Thanks again everyone!

 

At that price, I agree.

Now the QA1's....yeah WAY cheaper. The QA1's are SO the bee knees however.

 

Yea, I love the idea of the rebuild, but for just a bit more the lifetime warranty is really the way to go.

Just out of curiously, does anybody happen to know how long it takes the system to engage each mode going from one to the next? I mean, if you're getting on an on ramp in Performance, how long once you get onto the freeway does it take the system to fully change to Tour after you hit the switch? 40 milliseconds? 30 seconds? an hour? I don't see why it wouldn't be relatively quick but being a mechanical system vs the newer/more modern magnetic ride system; I can understand a bit of delay. Just curious, I haven't actually found that information anywhere.

Thanks again everyone!

 

You should be able to feel a difference immediately if you are driving in such a way that the suspension is "working" (i.e. hard turn).

The switch simply signals the controller to change actuator positions by sending electrical impulses to the shock actuators. But as I mentioned vehicle speed also is input to the FX3 system. So cruising down the freeway at 60 and you change the selector from TOUR to PERF, you may not feel anything.

But the actuators will change the shocks immediately upon twisting the switch. Same with hard acceleration where the MPH changes rapidly; the controller sends commands to the actualtors immediately.

Also, the shock rod itself doesn't turn a lot; IIRC something like only 90 degrees for the early FX3 system.

 

Ive got bad news. DRM says they dont offer any custom FX3 controller anymore.

I just put a post here calling out for Randy@DRM hoping he can explain this.

 

Not surprising considering the FX3 system went away in '95. The number of C4's on the road today that had FX3 could be pretty small by now and repair/replacement parts can be pricey.

And if DRM hasn't been selling many of their controllers, it wouldn't make sense to keep them on the shelf.

 

Mine has also FX3, is a 92 6speed.

In case I want to replace by a non driven system, which one should I mount?

I mean, I have seen Z51 model, sports, and other....I don't know which one would be the proper one.

My driving is quiet, I don't go to the track.

 

FX3 was available in two different ways for coupes. FX3 could be ordered by itself and the car would have come with the base suspension. The other way was having RPO Z07 (coupes only for this option) which came with much stiffer springs, larger sway bars, and offset bushings in the lower control arms. Z07 was a replacement for the earlier Z51 suspension system.

You can get Bilstein Z51-specific shocks or standard Bilstein shocks. Some members have used KYB Gas-A-just shocks in place of FX3 shocks and they provide a decent ride.

 

Thank very much for the information, I'll check the option codes label to check mine. The problem is that KYB cannot shipped by air

 

Can you tell me if I can use these shocks:

http://www.ecklerscorvette.com/1992+...1989-1996.html

Here you go my details

 

Well....you could but you shouldn't. You see that FE7 in front of the FX3 on the sticker.

Congratulations my friend you have a rare (about 800 made per year from 92-95) Z07 package car.

You would need the Bilstien shocks WITH Z51. Or just upgrade the FX3 shocks by re-valving and/or rebuilding them. The Z07 package was designed to work with the FX3 shocks.

The Z07 Performance package included Heavy Duty Lower Control Arm Bushings, 30mm SOLID front sway bar, 24mm solid rear sway bar, Stiffer front and rear springs, the FX3 shock package, and the J55 13" front brake setup.

Just sell your car if your just cruising around in it, you don't need the handling capabilities your car has in it. Just Kidding.

All kidding aside, your putting up with a harsher ride for no reason. I'd auto-x/track it to make it worth the harsher ride.